Optical film

Abstract

A film for optical applications which effectively prevents reflection of light on the surface of image display devices such as PDP, CRT and LCD, exhibits excellent scratch resistance and transmission of light, provides excellent adhesion between layers and can be produced at a low cost is disclosed. The film comprises (A) a high refractivity hard coat layer (the refractive index: 1.60 to 1.75, the thickness: 2 to 20 μm) comprising (a) an antimony-doped tin oxide having a needle shape (the average particle diameter along the major axis: 0.05 to 10 μm, the average aspect ratio: 3 to 100), (b) at least one other metal oxide and (c) a material cured with an ionizing radiation and (B) a low refractivity layer (the refractive index: 1.30 to 1.45, the thickness: 40 to 200 nm), which are successively laminated at least on one face of a substrate film.

1. A film for optical applications comprising (A) a high refractivity hard coat layer which comprises (a) an antimony-doped tin oxide having a needle shape having an average particle diameter along a major axis of 0.05 to 10 μm and an average aspect ratio of 3 to 100, (b) at least one other metal oxide and (c) a material cured with an ionizing radiation and has a refractive index in a range of 1.60 to 1.75 and a thickness in a range of 2 to 20 μm and (B) a low refractivity layer which has a refractive index in a range of 1.30 to 1.45 and a thickness in a range of 40 to 200 nm, layers (A) and (B) being successively laminated at least on one face of a substrate film. 
   
   
     2. A film for optical applications according to  claim 1 , wherein the other metal oxide of component (b) in layer (A) is at least one metal oxide selected from zirconium oxide, zinc antimonate and antimony pentaoxide. 
   
   
     3. A film for optical applications according to  claim 1 , wherein a content of entire metal oxides in layer (A) is 50 to 80% by weight, and a ratio of an amount by weight of component (a) to an amount by weight of component (b) is 4:1 to 1:3. 
   
   
     4. A film for optical applications according to  claim 1 , wherein layer (B) comprises porous silica and a siloxane-based polymer. 
   
   
     5. A film for optical applications according to  claim 4 , wherein layer (B) further comprises a silicone-based block copolymer. 
   
   
     6. A film for optical applications according to  claim 4 , wherein the porous silica in layer (B) has a specific gravity of 1.7 to 1.9, a refractive index of 1.30 to 1.36 and an average particle diameter of 20 to 100 nm. 
   
   
     7. A film for optical applications according to  claim 5 , wherein a content of the silicone-based block copolymer in layer (B) is 2 to 50% by weight. 
   
   
     8. A film for optical applications according to  claim 1 , wherein the hard coat layer of layer (A) is a hard coat layer having an antiglare property. 
   
   
     9. A film for optical applications according to  claim 1 , wherein the low refractivity layer of layer (B) has an antistatic property.